WO2013000695A1

WO2013000695A1 - Fuel injector

Info

Publication number: WO2013000695A1
Application number: PCT/EP2012/061014
Authority: WO
Inventors: Matthias Schnell
Original assignee: Robert Bosch Gmbh
Priority date: 2011-06-30
Filing date: 2012-06-11
Publication date: 2013-01-03
Also published as: DE102011078387A1

Abstract

The invention relates to a fuel injector (10; 10a), comprising an injector housing (18) that is hydraulically connected to a high pressure chamber (19) formed in the injector housing (18) via a high pressure connection (23), wherein the high pressure connection (23) can be connected to a vehicle-side high pressure line (28), and comprising a contact surface formed on the injector housing (18) for axially bracing the injector housing (18) in a receptacle (1) of an internal combustion engine, preferably by means of an auxiliary element (35; 35a) that generates an axial force (F) on the injector housing (18) by means of a clamping claw (5) in the region of the contact surface. According to the invention, the high pressure connection (23) is connected to the vehicle-side high pressure line (28) via a sealing seat (30) that is formed by the axial force (F) between the high pressure connection (23) and the high pressure line (28), and the high pressure line (28) is axially fixed in the auxiliary element (35; 35a) or in the clamping claw (5).

Description

description

title

Fuel injector prior art

The invention relates to a fuel injector according to the preamble of claim 1. Such a fuel! Njektor is known from DE 103 40 91 1 A1 of the Applicant. It is part of a so-called common-rail system in which each combustion chamber of a self-igniting internal combustion engine is supplied with fuel via a fuel injector from a high-pressure rail. For this purpose, the known fuel injector on an injector, which is arranged in a receptacle of an internal combustion engine, in particular in a cylinder head. The fuel! The injector has at its injector both a fuel port for connection to a vehicle-side, connected to the rail fuel line, and a plug connection for connection to a vehicle-side electrical connection line. In order to tightly secure the fuel injector in the receptacle, it is provided that the known fuel injector is pressed by means of a clamping claw in the receptacle, wherein the clamping claw via an auxiliary sleeve-shaped member generates an axial hold-down force. Due to the large variety of types, it is necessary to develop a special fuel injector or a special injector housing for each internal combustion engine, which differ in particular in the arrangement or orientation of the fuel connection and the plug connection. As a result, only a relatively small number of fuel injectors can be produced in each case, which results in relatively high production costs. Disclosure of the invention

Based on the illustrated prior art, the invention has the object, a fuel injector according to the preamble of claim 1 such that it is universally applicable for a variety of applications, i. Even with different customer requirements with regard to the arrangement of the vehicle-side high-pressure line or the electrical control line can always be applied or used in one and the same manner. This object is achieved in a fuel injector with the features of claim 1 according to the invention that the

High-pressure port is connected to the vehicle-side high-pressure line via a sealing seat, which is formed by an axial force between the high pressure port and the high pressure line, and that the high pressure line is axially fixed in the auxiliary member or the clamping claw. In other words, this means that the new concept of the fuel injector is characterized in that both the injector housing is pressed or pressed axially into the receptacle of the internal combustion engine via the auxiliary element (clamping sleeve) or the clamping claw simultaneously, and the high pressure port is formed between the injector and the motor vehicle side high-pressure line. The auxiliary element or the clamping claw thus takes over the prior art, an additional function, namely the formation of the fuel supply of the fuel! njektors by forming the tight connection between the high-pressure line and the injector.

Advantageous developments of the fuel according to the invention! Njektors are listed in the subclaims. All combinations of at least two of the features disclosed in the claims, the description and / or the figures fall within the scope of the invention.

In a preferred constructional implementation of the connection of the high-pressure connection with the vehicle-side high-pressure line, it is proposed that the sealing seat between the addressed components is formed by two positively cooperating sealing surfaces on the high-pressure connection and the high-pressure line. The sealing surfaces can be produced in a particularly simple and cost-effective manner if they are cone-shaped or cone-shaped.

In order to achieve an optimal introduction of force into the sealing seat while avoiding transverse forces, it is furthermore proposed that the auxiliary element is sleeve-shaped, and that the high-pressure line is received in a through bore formed in the longitudinal axis of the auxiliary element. A particularly good seal of the hydraulic connection between the

Auxiliary element (adapter sleeve) and the high pressure port on the injector housing is achieved when the auxiliary element transmits the axial force only to the injector housing over the area of the two sealing surfaces. As a result, the force exerted on the clamping claw is transferred completely to the injector housing via the sealing seat.

Another embodiment of the invention is concerned with the connection of a return port on the injector housing and a vehicle-side control line with an electrical plug connection to the injector. In this case, in a first variant of the embodiment in which the auxiliary element may be designed relatively simple, it is proposed that a return connection connectable to a vehicle-side return line and an electrical plug connection connectable to a vehicle-side control line be formed on the injector housing, and that between the auxiliary element and the Recording in the internal combustion engine, a receiving space for performing the return line and / or the drive line is formed.

The assembly of the mentioned additional lines is also particularly easily and safely solved when the drive line is received in a holding element, which is connected to the auxiliary element and axially secured.

In an alternative embodiment, in which the auxiliary element assumes additional functions, it is provided that a return connection which can be connected to a vehicle-side return line and an electrical plug connection which can be connected to a vehicle-side control line be attached to the injector housing are formed, and that the auxiliary element has a return flow, which is connectable on the one hand to the return port on the injector and on the other hand with the vehicle-side return line, and that the auxiliary element has a receiving bore for the vehicle-side control line.

The inventive arrangement and design of the auxiliary element (clamping sleeve) results in a relatively compact axial length of the fuel injector. This results in the problem of generating sufficiently high opening forces on one in the fuel! injector up and down movable nozzle needle. Both so-called piezoactuators and magnetic actuators are known from the prior art. Since piezoelectric actuators usually have a relatively large axial length, the fuel according to the invention is suitable! njek- tor in particular for the use of magnetic actuators for actuating the nozzle needle, as a so in the axial length relatively compact fuel injector is possible.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiment and from the drawing.

This shows in:

Fig. 1

and

Fig. 2 are longitudinal sections through different variants of inventive fuel injectors, if they are arranged in a cylinder head in an internal combustion engine, respectively in longitudinal section and

Fig. 3

to

Fig. 6 shows the assembly process of the fuel injector of FIG. 1 during different phases, each in longitudinal section.

The same components or components with the same function are provided in the figures with the same reference numerals. 1 shows a first fuel injector 10 according to the invention, as it serves for injecting fuel into a combustion chamber, not shown, of a self-igniting internal combustion engine. In this case, the fuel injector 10 is in particular part of a so-called common-rail injection system, which has a fuel injector 10 for each combustion chamber, which is supplied with fuel via a rail which serves to store high-pressure fuel.

The fuel! For example, the injector 10 is sealingly inserted into a receptacle 1 of a cylinder head 2 of the internal combustion engine designed as a bore, such that the end 3 of the fuel facing the combustion chamber of the internal combustion engine! Njektors 10 projects into the combustion chamber. The attachment of the fuel injector 10 in the receptacle 1 is carried out with a clamping claw 5 shown only in Figs. 5 and 6, which is screwed to the cylinder head 2, as is well known, and the fuel injector 10, at least indirectly, with an axial force F in the direction of a step 6 of the receptacle 1 is applied, against which the fuel injector 10 is applied.

The fuel! The injector 10 has, by way of example, a nozzle body 1 1, in which a nozzle needle 12 which is arranged movable up and down is guided, which serves to open or close injection openings in order to inject fuel into the combustion chamber of the internal combustion engine. The nozzle body 1 1 is axially braced with the interposition of a throttle plate 13 by means of a nozzle retaining nut 14 against an injector 15, which is part of an injector 18. The nozzle needle 12 arranged in a high-pressure chamber 19 of the injector housing 18 is moved up and down by means of a magnetic actuator 20, as known per se from the prior art and therefore not explained in detail. Within the injector housing 18, a high-pressure bore 21 is formed, which opens at the upper end of the injector 18 at the bottom 22 of a conical high pressure port 23 of the injector 18. In this case, the high-pressure connection 23 is preferably arranged in the longitudinal axis 24 of the injector housing 18 or the receptacle 1. Furthermore, the injector housing 18 laterally adjacent to the high-pressure connection 23 also has an electrical plug connection 25 via which the magnetic actuator 18 is activated or energized. The high pressure port 23 forms with its conical shape a first sealing surface 26 which cooperates positively with a second sealing surface 27, which is formed on a injector housing 18 facing the end of a vehicle-mounted high-pressure line 28 in a connecting piece 29. Here, the second sealing surface 27 is conical in shape, such that when a force is applied to the connector 29 in the direction of the high pressure port 23, the two sealing surfaces 26, 27 form a sealing seat 30, the introduction of the fuel from the rail via the vehicle-side high pressure line 28 into the high pressure bore 21 prevents the escape of fuel from the region of the high pressure port 23.

According to the invention, it is provided that the vehicle-side high-pressure line 28 is arranged in an auxiliary element, which is designed as a clamping sleeve 35. The clamping sleeve 35 has a running in the longitudinal axis 24, central through bore 36, at the fuel injector 10 end facing a diameter stage 37 is formed against which the connector 29 is applied, such that the connector 29 and thus the vehicle-side high-pressure line 28 axially against the direction of the axial force F fixed in the through hole 36 is received. The diameter stage 37 thus forms an axial stop for the connecting piece 29.

Parallel to the through hole 36, a return flow bore 38 is formed in the clamping sleeve 35, which opens on the injector 18 facing front side of the clamping sleeve 35, and forms a hydraulic connection with a in the respect to the return flow bore 38 from the injector 18 exiting return bore 39 which for returning from the high-pressure chamber 19 pressure-reduced fuel in a return region of the internal combustion engine is used. For this purpose, it may be provided that the clamping sleeve 35 has at its protruding from the receptacle 1 end a return pipe 41 which is connectable to a return hose 42. For sealing the clamping sleeve 35 at the outlet region of the receptacle 1, two sealing elements 43, 44 are further provided.

On the return flow bore 38 opposite side of the through hole 36, a further through hole 45 is formed, which serves to receive a vehicle-side control line 46 with a plug 47. By means of Control line 46 and the plug 47, the connector 25 is electrically contacted to the injector 18. In this case, the plug 47 is likewise received or fastened in the through-bore 45 in such a way that it makes electrical contact with the plug connection 25 when the clamping sleeve 35 is inserted into the receptacle 1. Preferably, the plug 47 is therefore, in analogy to

Connecting piece 29, axially secured in the through hole 45 received.

The assembly process of the fuel injector 10 in the receptacle 1 of the cylinder head 2 of the internal combustion engine will now be explained with reference to FIGS. 3 to 6: In a first step according to the Fig. 3, the fuel injector 10 is first inserted into the receptacle 1. 4, the clamping sleeve 35 is also introduced into the receptacle 1, wherein in advance the vehicle-side high pressure line 28 with the connector 29 and the vehicle-side control line 46 have been mounted with the plug 47 in the clamping sleeve 35. Possibly. can already be mounted on the return pipe 41, the return hose 42 already. The clamping sleeve 35 comes with its the fuel injector 10 facing end into abutting contact with the high-pressure port 23 on the injector 18. Thereafter, according to FIGS. 5 and 6, the clamping claw 5 brought into operative connection with the fuel injector 10 so that by applying the clamping claw 5 with the axial force F of the fuel injector 10 via the second sealing surface 27 of the clamping sleeve 35 and the high pressure port 23 and the first sealing surface 26 axially secured in the receptacle 1 and sealed. At the same time, when the axial force F is applied to the clamping sleeve 35, the hydraulic connection of the vehicle-mounted high-pressure line 28 to the high-pressure port 23 of the fuel is also achieved. Njektors 10 and the electrical contacting of the magnetic actuator 20 and its connector 25 is made via the plug 47.

Due to the fact that the clamping sleeve 35, with its end face facing the fuel injector 10, at least partially on the opposite end face of the

Fuel injector 10 and whose injector housing 18 rests, a uniform and full-surface introduction of the axial force F is achieved on the fuel injector 10. The modified fuel injector 10a shown in FIG. 2 differs from the fuel injector 10 in that the clamping sleeve 35a is used only for Receiving the vehicle-side high-pressure line 28 and the connector 29 is formed. Between the clamping sleeve 35a and the wall of the receptacle 1 thus an annular receiving space 49 is formed, which serves to receive the return hose 42a, which is formed opposite the return hose 42 according to FIG. 1 extended. The return hose 42a is in turn connected to a return pipe 51 at the top of the fuel injector 10a. In addition, the receiving space 49 also serves to receive the vehicle-side connection line 46 and the plug 47. Preferably, the plug 47 is axially secured in a holding element in the form of a plastic sleeve 52, which in turn encompasses the clamping sleeve 35a on its outer circumference and axially there secured connected to this.

The fuel described so far! Injectors 10, 10a can be modified or modified in many ways without deviating from the idea of the invention. So it is particularly conceivable to dispense with the clamping sleeve 35, 35a, and to arrange in the clamping sleeve 35, 35a guided or fixed components in the clamping claw 5, which is then formed extended, for example, with an extension.

Claims

claims

1 . A fuel injector (10; 10a) having an injector housing (18) which has a high-pressure connection (23) for the hydraulic connection of a high-pressure space (19) formed in the injector housing (18), the high-pressure connection (23) being connectable to a high-pressure line (28) on the vehicle side is, and wherein the injector (18) in a receptacle (1) of an internal combustion engine by means of a axial force (F) generating clamping claw (5) is axially at least indirectly clamped, characterized in that the high pressure port (23) with the vehicle side high pressure line (28 ) is connected via a sealing seat (30) which is formed by the axial force (F) between the high-pressure port (23) and the high-pressure line (28), and in that the high-pressure line (28) is axially fixed in an auxiliary element (35; is

or

the high-pressure connection (23) is connected to the vehicle-side high-pressure line (28) via a sealing seat (30) which is formed by the axial force (F) between the high-pressure connection (23) and the high-pressure line (28), and in that the high-pressure line (28 ) is received axially fixed in the clamping claw (5).

2. Fuel injector according to claim 1,

characterized,

the sealing seat (30) is formed by two positively cooperating sealing surfaces (26, 27) on the high-pressure connection (23) and the high-pressure line (28). 3. Fuel injector according to claim 2,

characterized, the sealing surfaces (26, 27) are conical or conical in shape.

Fuel! Ajector according to one of claims 1 to 3,

characterized,

in that the auxiliary element (35; 35a) is sleeve-shaped, and in that the high-pressure line (28) is accommodated in a through bore (36) formed in the longitudinal axis (24) of the auxiliary element (35;

5. Fuel! Ajector according to one of claims 2 to 4,

characterized,

in that the auxiliary element (35; 35a) transmits the axial force (F) exclusively to the injector housing (18) over the area of the two sealing surfaces (26, 27). 6. Fuel injector according to claim 4 or 5,

characterized,

in that a return connection (51) which can be connected to a vehicle-side return line (42) and an electrical plug connection (25) which can be connected to a vehicle-side control line (46) are formed on the injector housing (18), and that between the auxiliary element (35a) and the receptacle (35) 1) in the internal combustion engine, a receiving space (49) for carrying out the return line (42 a) and / or the drive line (46) is formed.

Fuel injector according to claim 6,

characterized,

in that the drive line (46) is accommodated in a holding element (52) which is connected to the auxiliary element (35a) and secured axially. 8. Fuel injector according to one of claims 4 or 5,

characterized,

in that a return port (39) which can be indirectly connected to a vehicle-side return line (42) and an electrical plug connection (25) which can be connected to a vehicle-side control line (46) are formed on the injector housing (18), and in that the auxiliary element (35) forms a return flow bore (38), on the one hand with the return port (39) on the injector (18) and on the other hand with the vehicle-side return line (42) is connectable, and that the auxiliary element (35) has a receiving bore (45) for the vehicle-side control line (46).

Fuel! Ajector according to one of claims 4 to 8,

characterized,

in that the end of the high-pressure line (28) facing the injector housing (18) is accommodated in a connecting piece (29) which is arranged axially fixed in the through-bore (36).

Fuel! Ajector according to one of claims 1 to 9,

characterized,

in that it has a magnetic actuator (20) for actuating a nozzle needle (12).